1. Field of the Invention
The present invention relates to a support leg member for supportively fixing a guide rail of a seat slide device to the floor of automobile. More particularly, the invention is directed to the structure of such support leg member.
2. Description of Prior Art
Most of automotive seats, such as a front seat, are provided with a seat slide device to allow for selective adjustment in position of the seat in the fore-and-aft direction thereof. As shown in FIGS. 1(A) and 1(B), a typical seat slide device, designated by (118), has a movable rail (120) (i.e. an upper rail) to be fixed on the seat cushion (SC) and a guide rail (112) (i.e. a lower rail) to be fixed on the floor (114) of automobile, wherein the movable rail (120) is sildably fitted, via rotatable elements such as rollers (122) and steel balls (124), in the lower rail member (120) such as to be movable along the longitudinal direction thereof or in the fore-and-aft direction. Designation (SB) denotes a seat back.
In this kind of seat slide device (118), the guide rail (112) has a longitudinally extending slit-like opening (126) formed in the upper wall thereof, whereas the movable rail (120) has a base portion (120a) slidably disposed within the guide rail (112) and a vertically extending portion (120b) which extends outwardly through the aforesaid opening (126) in the upward direction. To such vertically extending portion (120b), the seat cushion (SC) is securely connected via a bracket or the like. The guide rail (112) is provided with a front support leg member (110) and a rear support leg member (110) at the respective forward and rearward ends thereof in a securely fixed manner. Hence, the guide rail (112) is fixedly secured via those two leg members (110) to the floor (114).
With particular regard to the rear support leg member (110), as seen in FIG. 1(B), the well-known structure thereof is of such an offset configuration that the upper and lower securing portions (110-1) (110-2) thereof extend in a parallel direction opposite to each other with respect to the vertically bent central portion thereof, wherein all of those portions are formed integrally together. Namely, the upper securing portion (110-1) is defined at a side corresponding to the guide rail (112) and adapted for securely receiving the guide rail (112), while on the other hand, the lower securing portion (110-2) is defined at a side corresponding to the floor (114) and adapted for secure fixation thereto. In such support leg member (110), a pair of reinforcing pieces (116) are each provided at the respective right and left lateral sides thereof for the purpose of reinforcing the leg member itself and serving as a guide for allowing the guide rail (112) to be placed in position on the upper securing portion (110-1). The two reinforcing pieces (116) are formed by bending both right and left lateral regions of leg member (110) upwardly so as to erect symmetrically from the base portion (110a).
The automotive seat, in particular, a front seat, to which the foregoing slide rail device and leg members are applied (as in FIG. 1(A)), is normally equipped with a seat belt (BL). As shown in FIGS. 1(A) and 1(B), a seat belt anchor or its buckle (128) is provided for releasable connection with the seat belt (BL) and fixedly attached on the vertically extending portion (120b) of movable rail (120) associated with the seat slide device. In an emergency case or a collision, the seat belt (BL) is pulled by an excessive great load applied from an occupant on the seat (S). That is, referring to FIG. 1(B), the seat belt (BL) is strongly drawn in a direction to the center of seat (S) (i.e. in the arrow direction (F) ), with the result that a great force is caused via the buckle (128) (or seat belt anchor), which attempts to incline the movable rail (120) of the seat slide device in the same direction to the center of seat (S) (i.e. rightwards as viewed from FIG. 1(B)).
As stated earlier, the known support leg member (110) itself is normally high in rigidity due to the two reinforcing pieces (116), and thus, the guide rail (112) is firmly connected and supported thereby to the floor (114). Under such robust condition, if the excessive great load (i.e. the input load (F)) is caused, attempting to forcibly incline the movable rail (120) relative to the guide rail (112), it is highly possible that the input load (F) will be intensively exerted upon the outward edge (126a) of opeing (126) formed in the upper wall of guide rail (112).
Further, the input load (F) is transmitted to the reinforced support leg member (110), hence attempting to incline the guide rail (112) as well relative thereto. This means that a rivet (132), which connects those guidle rail and leg member together, is prone to receiving intensive exersion of the load (F), and therefore, it is more likely than not that the rivet (132) will be broken, depending on the degree of load (F) exerted thereon, which may also result in an undesried separation of the guide rail (112) from the leg member (110).
Heitherto, the above-noted problems have been solved by increasing the thickness of the the guide rail (112) to attain an increased rigidity enough to embracingly hold the movable rail (120) against the foregoing load (F) and by employing a more firmly fixing means, as by welding, to fix the the guide rail to the support leg member (110) so firmly enough to withstand the load (F), for the puprose of safety in the whole seat slide device. However, to increase the thickness of guide rail (112) will result in the guide rail itself being increased in size and weight. Also, the addition of such fixing means as welding will make more troublesome the steps of fixing the guide raild (112) to the support leg member (110). Consequently, those convnetional safety coutermeasures still require other separate elments and high costs involved, for which reason, a problem remains unsolved in the versatile and easy adaptability of support leg member for use in the seat.
In view of the above-stated drawbacks, it is a primary purpose of the present invention to provide improved structure of support leg member for use with a seat slide device, whcih is of a quite simplied structure for protecting the seat slide device against damage, without the necessity of increasing the size and weight of the guide rail of seat slide device.
To attain such purpose, according to the present inveniton, in combinatin with a seat slide device which includes a guide rail to be fixed at a side of a floor of automobile and an upper rail slidalby fitted in the guide rail, wherein a seat belt means is secruely provided at the guide rail, there is basically provided a structure of support leg member comprising:
a first securing portion defined at a side corresponding to the guide rail, on which first securing portion, the guide rail is securely mounted;
a second securing portion defined at a side corresponding to the floor of automobile, the second securing portion being adapted for fixation to that floor;
the first and second securing portions being formed so integrally together as to define a base portion in each of them;
a pair of reinforcing pieces which are so formed by bending two lateral regions of those first and second securing portions upwardly that the two reinforcing pieces erect respectively from two lateral sides of said base portion; and
an inclinable means defined in the base portion, which allows the support leg member to be deformed by a great load applied from said seat belt means in excess of a tolerable amount, thereby allowing inclination of the guide rail with respect to the support leg member.
Accordingly, the provision of only such inclinable means is sufficient to allow the great load to smoothly escape to the floor of automobile, thus simplifying the structure and eliminating the necessity of increasing the size and weight of the guide rail.
In one aspect of the present invention, the inclinable means may comprise an upward protuberant region or bead having a flat upper surface. This bead may be formed along a central line of the base portion of the first securing portion such as to space two lateral sides of the bead from the respective said two lateral sides of said base portion. Accordingly, there are defined a pair of spacings between a bottom wall of the guide rail and the base portion in such a manner that said pair of spacings are provided beneath the guide rail bottom wall in a symmetrical fashion relative to the central line of base portion, whereby, due to such pair of spacings, the guide rail is inclinable by the foregoing great load.
In another aspect of the invention, the inclinable means may comprise a downward protuberant region or bead formed along one lateral side of the base portion of first securing portion, which faces toward a center of said automotive seat. Thus, one spacing is defined beneath a bottom wall of said guide rail at a side facing toward the center of the automotive seat, whereby, due to such one spacing, the guide rail is inclinable by the foregoing great load.
In still another aspect of the invention, the inclinable means comprises an outward divergent fashion of said pair of reinforcing pieces, which is defined by bending them outwardly away from each other relative to said base portion so as to reduce a rigidity of said support leg member, whereby, only when the foregoing great is applied, the support leg member is buckled slantwise by the foregoing great load in at least one of two directions symmetric relative to the base portion, thereby allowing inclination of the guide rail towards a direction of the great load. Alternatively, the inclinable means may comprise an outwardly bent one of such pair of reinforcing pieces, which is defined by bending one of them outwardly relative to the base portion for the same purpose.
Other advantages and features of the present invention will become apparent from reading of the descriptions hereinafter, with reference to the annexed drawings.